California mudslides: Crews dig through debris

"We totally thought we were out of the woods", said Jennifer Markham, whose home escaped damage in both disasters. She posted on social media late Tuesday night, "the house in the back is gone".

"The house is destroyed, but you know, there's just so many others who are less fortunate".

Rescue efforts continue in Santa Barbara County, Calif., where the number of people missing in Tuesday's massive mudslides has dropped to eight from 17, while the death toll remained at 17 in the most recent official tally. Officials said numerous deaths are believed to be in the coastal Montecito area, where mudflows and floodwater have inundated areas downstream from where the Thomas Fire burned thousands of acres last month.

After a wildfire, burned vegetation and charred soil are especially susceptible to destructive mudslides because scorched earth does not absorb water well and the land is easily eroded when there are no shrubs. "She was really anxious about the baby, but she was completely fine once they were [inside]".

"They were in a voluntary evacuation area so they figured they were OK", said Weimer. Rescue crews worked up to 12 hours a day and risked stepping on nails or shattered glass, or being exposed to raw sewage, or dealing with leaking gas, said Deputy Dan Page, chief of a Los Angeles County Sheriff's Department rescue team.

"I think most people are really shocked at the extent of the damage and how big the impact was to the area", Brown said. "It's probably going to happen again and again", he said.

Crews begin clean-up efforts of Highway 101 after mudslides cause extensive damage to hundreds of buildings and caked highways with sludge, in Montecito, California, U.S., January 12, 2018. The Carpinteria Fire Department recorded a half-inch of rain in just 5 minutes Tuesday morning, officials said.

The USGS studies statistics of past landslides to predict how much rainfall will cause future natural disasters.

Mudslides have been a fact of life in Southern California for decades. Locations downhill and downstream from the burn scar left by a wildfire are susceptible to flash flooding, debris flow and mudslides, according to the National Weather Service. After the La Conchita landslide that killed 10 people in January 2005, the USGS said historical evidence showed that equally destructive landslides would keep happening. She said the region's summers have become hotter, and the droughts more severe.

The immediate areas where people were killed are under mandatory evacuation, and officials increased the size of the evacuation zone Thursday.